When MRNA sequences are translated in the ribosome, the amino acid sequence depends on the reading frame. There are three reading frames for any sequence. For the following sequence 5- GGCCUGCCUUGCGGA-3', the first G is the beginning of the first reading frame, the second G is the beginning of the second reading frame, and the first C is the beginning of the third reading frame. You obtain the amino acid sequence: Pro-Ala-Leu-Arg-Thr. Which reading frame is the correct one?

a. First reading frame
b. Second reading frame
c. Third reading frame
d. There is not enough information in the question